Researchers scramble to deal with dying oysters

A bacterium explodes in numbers, killing oyster larvae before
they can grow

Monday, June 09, 2008

MICHAEL MILSTEIN

The Oregonian Staff

An invisible microbe that thrives in warm ocean water has
undermined the Northwest's prized oyster supply,
killing billions of young larvae that mature into the
succulent shellfish known across the world.

The bacterium, Vibrio tubiashii, is related to another
species that can sicken people who eat raw shellfish. This
one doesn't bother people -- it kills shellfish in
their larval stage, before they latch onto rocks to grow.

An explosion of the microbe late last summer shut down an
Oregon shellfish hatchery that is one of the largest on the
West Coast, supplying larvae to about 70 oyster growers the
way seed companies provide crop seed to farmers.

The microbe also is the likely culprit in the disappearance
of recent generations of wild oysters from usually prolific
estuaries such as Willapa Bay on the southern Washington
coast.

"We're in a state of panic," said Robin
Downey, executive director of the Pacific Coast Shellfish
Growers Association, based in Olympia. "There is no
other word for it."

The crisis has the attention of local and state leaders,
including the governor. And scientists have rushed to devise
filters that can strain the lethal bacterium out of water
flowing through hatcheries.

Researchers say the rise of bacteria might be tied to the
same unusual ocean conditions -- possibly connected to
global climate change -- causing the suffocating "dead
zones" that have appeared off the Oregon coast in
recent summers.

The bacteria, long known in coastal waters at low levels,
seem to have taken off in the same areas and about the same
times as the dead zones. But it's unclear what
conditions have caused the bacteria to thrive.

"It's safe to say it's probably all of Oregon
and parts of California and Washington," said Ralph
Elston, a veterinarian with Aquatechnics in Sequim, Wash.,
who works with shellfish hatcheries.

Oysters grow for a few years before they're big enough
to eat, so those showing up in restaurants now predate the
recent bacterial boom that killed young oysters. Growers
predict the loss of those generations of oysters will shrink
supply and probably drive up prices later this year.

"It's going to have some major effects on the
industry in the next year or so," said Bill Taylor of
Taylor Shellfish Farms, which hatches and grows oysters on
Washington's Hood Canal and also has been hammered by
the bacteria this spring. "There's not going to be
enough marketable oysters to sell."

Besides oysters, geoducks grown farther north on the West
Coast are at risk. Clams and mussels seem less vulnerable,
though fisheries officials have noticed a lack of young
razor clams along some areas of the coast.

Hatcheries sound alarm

State biologists don't monitor wild shellfish as they
do key fish species such as salmon. Shellfish hatcheries,
which grow larvae in water pumped from the ocean, were the
first to realize that young oysters were dying.

"The hatcheries are really the canary in the mine
shaft," said Chris Langdon, a professor at Oregon State
University's Hatfield Marine Science Center in Newport.
"There hasn't been monitoring of this bacteria on
large scales."

West Coast growers produce more than $100 million worth of
commercial shellfish each year, with oysters by far the
largest share. Cultivated oysters are mainly Pacific
oysters, originally imported from Japan and different from
native West Coast oysters.

But researchers said the bacteria probably also are
affecting wild shellfish.

Oyster larvae suddenly disappeared from Willapa Bay last
year, said Alan Trimble, a University of Washington
researcher who works at the bay. He suspects the bacteria
contributed to poor reproduction of native oysters and razor
clams in bays and coastal beaches.

"When the larvae die in the water column, it isn't
just Pacific oysters; the others disappear also," he
said in an e-mail from Namibia, where he is on leave.

That could affect the rest of the marine food chain, because
many other forms of marine life eat young shellfish.

Business shuts down

Late last summer, the bacteria multiplied to levels that
shut down Whiskey Creek Hatchery on Netarts Bay. Tiny oyster
larvae that usually swim busily under a microscope instead
looked shrunken and feeble as a toxic enzyme secreted by the
bacteria destroyed them, said Sue Cudd, who, with her
husband, Mark Wiegardt, runs the hatchery.

The hatchery usually produces many billions of oyster larvae
each year but couldn't produce any once the bacteria
invaded in August. Wiegardt and Cudd had nothing to send to
growers that depend on them for their seed stock.

"We have the weight of a lot of people depending on
us," Wiegardt said. "If we don't figure out
this problem, people are going out of business."

The hatchery burned through its reserve funds and was about
to give up. "I had nowhere to go," Cudd said.

Then the couple found help from the Hatfield Marine Science
Center, which had similar trouble at its hatchery in 2005.
Researchers there developed a filtration system that uses a
combination of ultraviolet light and other methods to remove
the bacteria from water entering the hatchery.

Other shellfish growers, many of them the hatchery's
customers, donated money to hire Alan Barton, a former
Hatfield researcher, to design a similar system at the
Whiskey Creek hatchery.

That's now up and running at a cost of about $180,000,
although it handles only enough water for the hatchery to
produce about half its normal oyster crop of close to 50
million larvae a day. It will cost an additional $80,000 to
expand the system to provide a full water supply.

"This affects a huge West Coast oyster industry that
goes all the way to the oysters on your plate," said
Mark Labhart, a Tillamook County commissioner who is trying
to help the hatchery find financial assistance to boost the
filter system.

Finding out why

Concentrations of Vibrio have spiked as high as 1 million in
1 milliliter of water -- at least 100 times usual levels --
and remain higher than normal, Barton said. The bacterium
also took off in 1998, when an El Nino pattern warmed
coastal waters, though not nearly as severely as it has
recently, Elston said.

He suspects some of the same factors Oregon State
researchers have connected with dead zones along the coast:
strong but intermittent upwelling of deep water that pushes
rich nutrients toward the surface.

Langdon said the deep water also might be a source of the
oyster-killing bacteria.

Though the deep water is cold, its nutrients could combine
with warm surface waters to nourish the microbes, Elston
said. "The conditions were just absolutely optimal for
a bloom."

The bacteria might now have collected in the sediments of
inlets and bays, and Wiegardt can't help but wonder
what's happening to wild shellfish in the oceans.
"I don't think it's just about us anymore.
It's about what's going on in the marine
environment."

Researchers scramble to deal with dying oysters

A bacterium explodes in numbers, killing oyster larvae before
they can grow

Monday, June 09, 2008

MICHAEL MILSTEIN

The Oregonian Staff

An invisible microbe that thrives in warm ocean water has
undermined the Northwest's prized oyster supply,
killing billions of young larvae that mature into the
succulent shellfish known across the world.

The bacterium, Vibrio tubiashii, is related to another
species that can sicken people who eat raw shellfish. This
one doesn't bother people -- it kills shellfish in
their larval stage, before they latch onto rocks to grow.

An explosion of the microbe late last summer shut down an
Oregon shellfish hatchery that is one of the largest on the
West Coast, supplying larvae to about 70 oyster growers the
way seed companies provide crop seed to farmers.

The microbe also is the likely culprit in the disappearance
of recent generations of wild oysters from usually prolific
estuaries such as Willapa Bay on the southern Washington
coast.

"We're in a state of panic," said Robin
Downey, executive director of the Pacific Coast Shellfish
Growers Association, based in Olympia. "There is no
other word for it."

The crisis has the attention of local and state leaders,
including the governor. And scientists have rushed to devise
filters that can strain the lethal bacterium out of water
flowing through hatcheries.

Researchers say the rise of bacteria might be tied to the
same unusual ocean conditions -- possibly connected to
global climate change -- causing the suffocating "dead
zones" that have appeared off the Oregon coast in
recent summers.

The bacteria, long known in coastal waters at low levels,
seem to have taken off in the same areas and about the same
times as the dead zones. But it's unclear what
conditions have caused the bacteria to thrive.

"It's safe to say it's probably all of Oregon
and parts of California and Washington," said Ralph
Elston, a veterinarian with Aquatechnics in Sequim, Wash.,
who works with shellfish hatcheries.

Oysters grow for a few years before they're big enough
to eat, so those showing up in restaurants now predate the
recent bacterial boom that killed young oysters. Growers
predict the loss of those generations of oysters will shrink
supply and probably drive up prices later this year.

"It's going to have some major effects on the
industry in the next year or so," said Bill Taylor of
Taylor Shellfish Farms, which hatches and grows oysters on
Washington's Hood Canal and also has been hammered by
the bacteria this spring. "There's not going to be
enough marketable oysters to sell."

Besides oysters, geoducks grown farther north on the West
Coast are at risk. Clams and mussels seem less vulnerable,
though fisheries officials have noticed a lack of young
razor clams along some areas of the coast.

Hatcheries sound alarm

State biologists don't monitor wild shellfish as they
do key fish species such as salmon. Shellfish hatcheries,
which grow larvae in water pumped from the ocean, were the
first to realize that young oysters were dying.

"The hatcheries are really the canary in the mine
shaft," said Chris Langdon, a professor at Oregon State
University's Hatfield Marine Science Center in Newport.
"There hasn't been monitoring of this bacteria on
large scales."

West Coast growers produce more than $100 million worth of
commercial shellfish each year, with oysters by far the
largest share. Cultivated oysters are mainly Pacific
oysters, originally imported from Japan and different from
native West Coast oysters.

But researchers said the bacteria probably also are
affecting wild shellfish.

Oyster larvae suddenly disappeared from Willapa Bay last
year, said Alan Trimble, a University of Washington
researcher who works at the bay. He suspects the bacteria
contributed to poor reproduction of native oysters and razor
clams in bays and coastal beaches.

"When the larvae die in the water column, it isn't
just Pacific oysters; the others disappear also," he
said in an e-mail from Namibia, where he is on leave.

That could affect the rest of the marine food chain, because
many other forms of marine life eat young shellfish.

Business shuts down

Late last summer, the bacteria multiplied to levels that
shut down Whiskey Creek Hatchery on Netarts Bay. Tiny oyster
larvae that usually swim busily under a microscope instead
looked shrunken and feeble as a toxic enzyme secreted by the
bacteria destroyed them, said Sue Cudd, who, with her
husband, Mark Wiegardt, runs the hatchery.

The hatchery usually produces many billions of oyster larvae
each year but couldn't produce any once the bacteria
invaded in August. Wiegardt and Cudd had nothing to send to
growers that depend on them for their seed stock.

"We have the weight of a lot of people depending on
us," Wiegardt said. "If we don't figure out
this problem, people are going out of business."

The hatchery burned through its reserve funds and was about
to give up. "I had nowhere to go," Cudd said.

Then the couple found help from the Hatfield Marine Science
Center, which had similar trouble at its hatchery in 2005.
Researchers there developed a filtration system that uses a
combination of ultraviolet light and other methods to remove
the bacteria from water entering the hatchery.

Other shellfish growers, many of them the hatchery's
customers, donated money to hire Alan Barton, a former
Hatfield researcher, to design a similar system at the
Whiskey Creek hatchery.

That's now up and running at a cost of about $180,000,
although it handles only enough water for the hatchery to
produce about half its normal oyster crop of close to 50
million larvae a day. It will cost an additional $80,000 to
expand the system to provide a full water supply.

"This affects a huge West Coast oyster industry that
goes all the way to the oysters on your plate," said
Mark Labhart, a Tillamook County commissioner who is trying
to help the hatchery find financial assistance to boost the
filter system.

Finding out why

Concentrations of Vibrio have spiked as high as 1 million in
1 milliliter of water -- at least 100 times usual levels --
and remain higher than normal, Barton said. The bacterium
also took off in 1998, when an El Nino pattern warmed
coastal waters, though not nearly as severely as it has
recently, Elston said.

He suspects some of the same factors Oregon State
researchers have connected with dead zones along the coast:
strong but intermittent upwelling of deep water that pushes
rich nutrients toward the surface.

Langdon said the deep water also might be a source of the
oyster-killing bacteria.

Though the deep water is cold, its nutrients could combine
with warm surface waters to nourish the microbes, Elston
said. "The conditions were just absolutely optimal for
a bloom."

The bacteria might now have collected in the sediments of
inlets and bays, and Wiegardt can't help but wonder
what's happening to wild shellfish in the oceans.
"I don't think it's just about us anymore.
It's about what's going on in the marine
environment."